printscreen
join:2003-11-01
Juana Diaz, PR
 ·Choice Cable TV
 ·Coqui/PRTC
1 edit | Cable vs DSL (not another which is best topic)
From cable to DSL | 
DSL traffic while idle | 
Cable traffic while idle |
 Read on.
I have been using DSL for a number of years now but last week decided to give cable a try after they doubled their speeds recently. In fact, they have doubled their speeds twice in the last year or so while the telephone company has remained stuck in their offerings (now much more expensive compared to cable) for a few years.
But this is not what I am asking. Ever since I started using cable I am noticing that there is constant traffic coming into the computer. I never noticed this when using DSL. Attached are images of DU Meter showing this. Since I still have DSL active I can just switch from one to another by just swapping the network cable coming from the proper device.
First image shows the moment I unplugged the cable modem and plugged the DSL modem. Second image shows DSL modem traffic when the computer is "idle" and third image shows cable modem traffic with the computar idle as well.
Apart from the difference in speed, as far as the computer is concerned, there is no difference between them. The only major difference is that the DSL modem is a 2Wire Home Portal which is a router and wireless access point and the cable modem is simply a Morotola SB5101 modem. The DSL modem has a firewall and NAT. I did not install any software related to the cable modem. I just brought it in from the cable company offices and plugged it into the network port and the coax cable without doing anything else.
What can be the source of this traffic? No running process seems to be listening to any port thay may cause this. Just curious. |
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printscreen
join:2003-11-01
Juana Diaz, PR | I forgot. If I hit the "Standby" button in the cable modem this traffic stops immediately. |
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tschmidt
Premium,MVM
join:2000-11-12
Milford, NH | reply to printscreen
Cable is shared at the Node so it may be background low level stuff.
Do you have a router? It should log incoming traffic. Mine reports a constant barrage of port scans and attempted telnet connections.
/tom |
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printscreen
join:2003-11-01
Juana Diaz, PR
·Choice Cable TV
·Coqui/PRTC
| While googleing for this thing I wound up in the Comcast forum here in BBR and found a topic about this with what seems to be the explanation. I installed a packet sniffer as suggested by one poster there and found a large number of ARP requests coming from what I suppose is the node. Very little incoming activity aside from that. Seems to be the nature of the beast.
No router at this time but might be installing one in the future. Will a router filter this? |
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tschmidt
Premium,MVM
join:2000-11-12
Milford, NH
 ·Hollis Hosting
·Verizon Online DSL
·Fairpoint Communic..
| said by printscreen  :Will a router filter this? If you mean by "filter" will PCs connected to the LAN see this type of traffic, then yes a router will process these requests and not pass them the the LAN.
ARP scope is limited to the LAN they are on. With a router you will see ARPs on the LAN and separately ARPs on the Cable network.
/tom |
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printscreen
join:2003-11-01
Juana Diaz, PR | Yes, that is what I meant. If all that node traffic would not be visible behind a router. |
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